This program is directed at an increased understanding of regulation of the circulation. It approaches regulation on a variety of levels, extending from effects of emotion to effects of peripheral receptors. We consider regulation of particular vascular beds (coronary, skin, muscle, splanchnic), distribution of blood flow, and detailed examination of the microcirculation. Experimental preparations extend from anesthetized animal preparations through intact, unanesthetized experimental animals, and humans. We seek to investigate details of regulation in arterioles, precapillary sphincters (i.e., at sites where ultimate control is investigated), and the importance of local metabolic control versus autonomic control. Where possible, we will produce a quantitative description of the phenomena under study. We hope to understand the quantitative significance of regional vasomotor activity in the redistribution of blood flow and in regulation of total peripheral resistance and blood pressure in a variety of conditions.